1. Field of the Invention
The present invention relates to a technology in which a print instruction is given to a printing system to which a plurality of printing apparatuses is physically connected (hereinafter this configuration will be referred to as a tandem-connected printing apparatus) and one printed matter is created for one printing medium (hereinafter this creation of the printed matter will be referred to as tandem printing).
2. Description of the Related Art
Recently, in order to give an added value to a printed matter created by combining process colors such as CMYK, a particular color expressing a color that cannot be expressed by process colors or a transparent color intended to give a glossy feeling are increasingly used. However, since these particular colors and transparent color can be handled only by a special printing apparatus in most of the cases, a value-added printing is realized by combining printing apparatuses in charge of process-color printing, particular-color printing, and transparent-color printing, respectively.
For example, process-color printing is performed by a given printing apparatus, particular-color printing is performed on the printed matter by another printing apparatus, and transparent-color printing is performed on the printed matter by still another printing apparatus. If each printing apparatus is of an electrophotographic type, in each printing process by each printing apparatus, toners are sequentially placed on the same printing medium (paper, sheet). As a result, in the second printing process (second printing apparatus) and after, a characteristic of the printing medium becomes different from that of the first printing process due to changes in weight and surface properties caused by placement of the toners. Since the characteristic of the printing medium is changed in each printing process in such tandem printing, several problems are caused.
One of the problems is a curling phenomenon. In the electrophotographic type, the curling phenomenon of the printing medium is caused in a process in which the printing apparatus fixes the toner.
The curling phenomenon means that paper on which a toner image is transferred, fixed and printed and output is curved when paper is used as the printing medium. If curling occurs, paper jamming or deterioration in a stacking capacity of a tray is caused. Thus, in order to overcome the curling in the printing apparatus, decurling process needs to be executed. However, the degree of occurrence of the curling phenomenon is changed depending on an adhesion-amount-of-toner. Therefore, depending on the adhesion-amount-of-toner in the first session of the printing process (first printing process), the curling cannot be overcome only by executing the decurling process according to the printing medium characteristic in the second session of the printing process (second printing process), which is a problem. In order to solve this problem, hitherto, a technology in which a curling correction amount by decurler in the second printing process is appropriately changed on the basis of printing medium information and the adhesion-amount-of-toner in the first printing process has been known (See Japanese Patent Laid-Open No. 2009-288452).
However, with the above prior-art technology, though the curling phenomenon caused by the tandem printing can be handled, other problems caused by the change in the characteristics of the printing medium in each printing process cannot be handled. For example, the other problems caused by the tandem printing include a problem of defective images such as defective fixation of the toner, defective surface properties and the like in the electrophotographic type. They are problems caused since appropriate printing process is not applied to the printing medium.
Also, in the prior-art technology, automatic association between a print job (and each page in a print job) and a curling correction amount corresponding to each page between respective printing apparatuses is not disclosed. Hitherto, if printed matter with the same adhesion-amount-of-toner is to be output using the same printing medium, it can be performed continuously since the same curling correction amount can be applied in the decurling process. However, in a continuous job or a continuous page output in which the printing medium or the adhesion-amount-of-toner is changed, the printing medium in the first printing process might be changed. Also, if the adhesion-amount-of-toner on the printing medium on every page is changed by the first printing process, the curling correction amount required in the second printing process is changed. Thus, in the curling correction in the second printing process, an unintended curling correction amount might be applied to an unintended page.
Therefore, there is a problem that the continuous job or continuous page output in which the type of the printing medium or the adhesion-amount-of-toner is changed needs intervention of manpower.
In the tandem-connected printing apparatus, it is intended that a plurality of apparatuses creates one printed matter in coordination without intervention of manpower, and solution of this problem is important.